I have only been in the pits at Texas Motor Speedway. Relating to that I would suggest a wide angle lens. Maybe a 12-24 if you have it. I see you also have the 50-135 which would be very handy and is a great lens for more detailed shots of the pit. Unfortunately I got to go back in the late 90's before DSLR. You will find all sorts of bright colors and tools to take shots of along with the cars and drivers. also, Earplugs if you are staying long there.

Tailgate the pros. I'm sure there will be a herd of pros roaming about - more than likely flocking around Danica Patrick. See what's getting their interest, subjects,angle, lens type they're using, etc.

I guess I am still different, I would not tailgate anyone. Just go your own way, try to keep some of the background people in your shots, the mechanics, the parts chasers, the pit crews. Oh definitely get pics of the cars and any real favorite drivers you have. There are a lot of people behind the scenes that have short fuses, they can blow up over nothing if they are having a bad day. Just lay low and do not attract attention to yourself, shoot it like you would take street pics.
Most of all have fun.